The present invention relates to a method of collective melting treatment of radioactive miscellaneous solid wastes, without classifying them, by using a cold crucible induction melting process, and more specifically, to a method capable of collectively reducing the volume of and solidifying various kinds of radioactive solid wastes, such as inflammables, metals, glasses and other nonflammables.
Nuclear facilities or the like produce large amounts of radioactive miscellaneous solid wastes which contain in mixed form various kinds of substances, such as inflammables, metals, glasses and other nonflammables. Since such radioactive miscellaneous solid wastes have different radioactive levels or mixture ratios among various wastes-producing facilities, it is impossible to generally compare the radioactive miscellaneous solid wastes. However, in high-level solid wastes generated from reprocessing facilities, various substances are mixed, such as metals, woods, rags, etc. Although the mixture ratio differs with each operational condition, it is reasonably estimated that metals account for about 90% and the remainder consists of inflammables (rags or the like) and nonflammables (plastic sheets or the like).
For this reason, it is desired to develop an art capable of collectively and easily treating, i.e. volume-reducing and solidifying the radioactive miscellaneous solid wastes in which the waste components are not clearly classified and which exhibit various mixture ratios. A conventionally proposed method of melting treatment is a high-temperature melting method such as plasma melting.
However, in such a conventional high-temperature melting art, molten matter makes direct contact with constituent materials of a melting furnace, e.g. refractory materials of furnace-wall or electrodes, under melting temperature conditions for a substance to be melted. Accordingly, a counter-measure against high-temperature erosion (allowance for erosion or replacement of constituent materials) and the limitation of a melting temperature (the upper limit is the temperature below which the strength of constituent materials can be assured) become great problems. Specifically, the life of the constituent materials is short owing to severe high-temperature erosion, and large amounts of secondary wastes are generated as a result of the replacement of eroded constituent materials. In addition, since the melting temperature is limited, it is difficult to effect melting treatment of high melting-point metals.